The high rates of overweight and obesity, currently occurring in children, underline the urgent need for preventive strategies in early life before excess weight is gained.

In this study, the alleviating obesity property of chlorophyll supplementation in early life is investigated using a 4‐week‐old C57BL/6J male mice model with obesity induced by high‐fat diet (HFD). The present study finds that chlorophyll supplementation in early life can effectively retard body weight gain, improve glucose tolerance, as well as reduce low‐grade inflammation in HFD‐fed mice. Consequently, high‐throughput sequencing of the 16S rRNA demonstrates that chlorophyll supplementation significantly reversed the HFD‐induced gut dysbiosis, as evidenced by the decreased Firmicutes‐to‐Bacteroidetes ratios as chlorophyll is introduced. Furthermore, in chlorophyll‐fed mice, the increased abundance of Blautia and norank_f_Bacteroidales_S24‐7_group, and the decreased abundance of Lactococcus and Lactobacillus, bring about the possibility that chlorophyll's alterations to the gut microbiota composition would be the main factors for dietary chlorophyll alleviating obesity‐related indexes.

Taken together, these results reveal that the intake of chlorophyll in early life may propel healthy weight management and produce beneficial effects against potential obesity in later life.